1. Field of the Invention
The present invention generally relates to a temperature control method and a temperature control device for use in the temperature control method. In particular, the present invention relates to a temperature control method in which a controlled part, such as an electronic part, is subjected to heating or cooling so that the controlled part is set at a given temperature different from a normal temperature, in order to carry out evaluation and/or testing of the controlled part.
2. Description of the Related Art
In the following, the electronic parts are semiconductor integrated circuit devices, such as IC and LSI, which will be referred to as semiconductor devices.
While the electronic parts are required to attain high integration and advanced features, the environment and conditions in which they are used have become severe. There is the increasing demand for higher reliability of the electronic parts, including the temperature characteristics thereof.
The improvement of the MPU (micro processing unit) for high-end servers, among various semiconductor devices, in the speed and the parallel processing of plural arithmetic computations is advancing quickly. As a result, the increase of the electric power which is consumed by a single semiconductor device (semiconductor chip), i.e., the raise of the power consumption, is progressing.
Although the power consumption of a conventional MPU was in a range of 10 watts to 30 watts, the power consumption of the current MPU is now in a range of 100 watts to 200 watts. It is readily expected that the power consumption of a MPU in the near future will exceed 300 watts.
The operation of a semiconductor device causes a temperature rise due to the self-heating and the surrounding environment, and the operation of the semiconductor device becomes unstable. The above-mentioned temperature rise is fundamentally proportional to the power consumption of that semiconductor device.
For this reason, when conducting the performance test of a semiconductor device etc., it is indispensable to control the temperature of a semiconductor device to a desired temperature at the time of operation.
In order to realize the high integration and advanced features of semiconductor devices, the miniaturization and high-density structure of the functional devices, such as transistors, the wiring, etc., are attempted, and the calorific value per unit area (heat density) tends to increase.
For this reason, when conducting the performance test of semiconductor devices, high cooling efficiency is needed and advanced technology of temperature control is demanded.
The power consumption of a semiconductor device greatly varies depending on the kind of the semiconductor device (the difference of functions, capacity, etc.). Namely, the temperature rise due to the self-heating varies for every semiconductor device.
For this reason, in order to control the temperature of a semiconductor device to a desired value at the time of operation, it is necessary to change the cooling temperature according to the electric power which is consumed by the semiconductor device of concern.
Unless the cooling temperature is selected, the difference of the power consumption appears as a difference of the temperature (junction temperature Tj) of the semiconductor device of concern, and exact operation of the semiconductor device cannot be checked and compensated.
Therefore, the checking and compensating of the operating characteristics cannot be performed to various kinds of semiconductor devices with which the heat generating characteristics differ under the controlled temperature condition or at a constant low temperature.
As for the semiconductor device with which high integration and advanced features thereof are implemented, the power consumption greatly varies with the states of operation (the contents of operation) at the time of operation as mentioned above.
Also when conducting the testing for checking and compensating the operating characteristic of a semiconductor device, the power consumption, i.e., the temperature of a semiconductor device, will change with the respective testing items sharply. For this reason, it is necessary to control the temperature of a semiconductor device in accordance with the state of operation and the testing item of the semiconductor device.
The relation between the cooling temperature of the semiconductor device surface and the temperature of the semiconductor device itself is represented by the formula:Tj=Tc+P×Rjc 
where “Tj” denotes the temperature of the semiconductor device itself, “Tc” denotes the surface temperature of the cooled portion (the surface of the semiconductor chip itself, the surface of the package accommodating a semiconductor chip, etc.) of the semiconductor device, “P” denotes the power consumption of the semiconductor device at the time of operation (in W), and “Rjc” denotes the thermal resistance between the semiconductor device itself and the cooling portion (in degrees C/W).
Conventionally, in order to examine and evaluate the temperature characteristics of a semiconductor device, the cooling processing or heat-treatment is given to the semiconductor device of concern in the manufacture process, and evaluating and examining the operating characteristics in the respective states is conducted.
In order to carry out the above-mentioned heat-treatment and cooling processing, the cooling element, such as a heat conductive material provided with radiation fins, or the heater element, such as a heater, is contacted to the package accommodating the evaluated/tested semiconductor device. These elements are used so that the semiconductor device under the evaluation/testing is cooled or heated to a desired temperature, and the temperature characteristics of the semiconductor device are evaluated.
Several conventional systems for examining and evaluating the operating characteristics of the semiconductor device in the respective states by giving the cooling processing or heat treatment to the evaluated/tested semiconductor device are known. For example, see Japanese Laid-Open Patent Application No. 61-269085, Japanese Laid-Open Patent Application No. 63-091577, and Japanese Laid-Open Patent Application No. 2001-526837.
Japanese Laid-Open Patent Application No. 61-269085 discloses a temperature test system using a plate-like heating-medium part, having outside dimensions equivalent to those of the electronic part, in which the temperature sensor is embedded. In the temperature test system, the thermoelectric effect element, such as a Peltier device (Peltier effect element), and the resistance heating element are arranged in a staggered formation on one principal surface of the heating medium part.
The heating medium part is made of a thermally conductive material, such as aluminum (Al). And in the state where the other principal surface of the heating medium part is contacted to the examined/evaluated electronic part, the thermoelectric effect element is operated (the resistance heating element is also operated if needed), the cooling or heating is performed, so that the temperature characteristics of the electronic part are evaluated.
In the above-mentioned composition, the thermoelectric effect element and the resistance heating element are arranged in a staggered formation on the principal surface of the heating medium part which has an area equivalent to the contact surface of the electronic part evaluated or tested.
According to the above composition, the heating medium part has the area equivalent to the area of the electronic part of concern, and the heating medium part has a thickness equivalent to that of the electronic part. The heat capacity of the heating medium part is comparatively small, and the rapid temperature change in the electronic part cannot be absorbed or diffused. And the electronic part is subjected to the rapid cooling by the thermoelectric effect element, and a thermal damage will be given to the electronic part.
Japanese Laid-Open Patent Application No. 63-091577 discloses a cooling and heating device in which the Peltier device and the radiation fin are arranged with a spacer interposed between them on one principal surface of a contact plate in which the temperature sensor is embedded.
And in the state where the other principal surface of the contact plate is contacted to the examined/evaluated semiconductor device, the Peltier device is operated so that the heating or the cooling is performed, and the temperature characteristics of the semiconductor device are evaluated.
In the above-mentioned composition, to the semiconductor device being examined, two or more Peltier devices are laminated on one principal surface of the contact plate. Also there is the composition in which the radiation fin is arranged further.
According to the above composition, the heat dissipation is processed through the contact plate, the Peltier device, the spacer and the radiation fin in this order when cooling the semiconductor device. The passage of the heat conduction is comparatively long, the heat capacity is comparatively large, and it is difficult to achieve rapid cooling or rapid heating of the semiconductor device.
Moreover, Japanese Laid-Open Patent Application No. 2001-526837 discloses a temperature control system in which the heat sink is disposed on one principal surface of the electric heater. And in the state where the other principal surface of the electric heater is directly contacted to the examined/evaluated electronic device (the semiconductor device with the built-in temperature sensor), the electric heater is operated so that the heating is performed and the heat is radiated by using the heat sink, so that the temperature characteristics of the electronic device are evaluated. In the above-mentioned composition, the heat sink is allocated via the electric heater to the electronic device being examined.
According to the above composition, there is no unit for cooling directly the semiconductor device (the evaluated/tested electronic device) to a lower temperature, and it is difficult to conduct the above-mentioned evaluation or testing of the semiconductor device in such a cold condition.
Moreover, the electric heater is interposed between the heat sink and the semiconductor device (the evaluated/tested electronic device), and the heat produced from the evaluated/tested electronic device is dissipated through a high thermal resistance region. The heat conduction passage is long, and the heat capacity is comparatively large, and it is difficult to carry out prompt cooling or heating of the semiconductor device.